1. Field of the Invention
The present invention relates to a treatment apparatus and a treatment method, for example, for coating a substrate with a resist film and developing the exposed resist film.
2. Description of the Related Art
In a manufacturing process of a semiconductor device, there are a series of processes called photolithography in which a resist film is formed on a semiconductor wafer (referred to as a wafer hereinafter), a circuit pattern and the like are reduced by photo-technology to expose the resist film, and the exposed resist film is developed.
In the photolithography processes, as a circuit pattern becomes fine, it becomes important to precisely control the line width of a resist pattern. The line width of a resist pattern changes depending on various conditions such as conditions in resist coating.
For example, a spin coating method is one of methods for coating a wafer with a resist solution. In the spin coating method, with an increase in the rotational frequency of a wafer, centrifugal force increases, whereby film thickness becomes smaller and line width changes. Specifically, film thickness is influenced by the rotational frequency of a motor of a spin chuck, and moreover varied by the temperature and humidity of atmosphere. Therefore, hitherto, a resist film is formed on a test wafer, for example, once in several days to set a desired value of the rotational frequency of the motor required for obtaining optimum film thickness. In a mass-producing process, the temperature and humidity of atmosphere are controlled so as to be fixed, and the formation of a resist film (coating of a resist solution) is performed with the desired value.